1. Field of the Invention
The present invention relates to a process for producing stabilized N-(.alpha.-alkoxyethyl)formamide. This compound is useful as an intermediate for the synthesis of N-vinylformamide.
2. Description of the Prior Art
A process for producing N-(.alpha.-alkoxyethyl)formamide is disclosed in U.S. Pat. No. 4,567,300. It consists of reacting formamide with acetaldehyde in the presence of a basic catalyst to give N-(.alpha.-hydroxyethyl) formamide and alkoxylating it subsequently. According to the disclosure, the basic catalyst should preferably be a weakly basic one which is composed of a strong base (such as hydroxide of lithium, sodium, or potassium) and a weak acid ( such as organic acid, phenol, sulfurous acid, phosphorous acid, carbonic acid, and phosphoric acid) which has a pK.sub.a value of 4-15. Sodium carbonate is used as the basic catalyst in Example.
The above-mentioned process proceeds rather stoichiometrically, but the actual yield is low after purification that follows alkoxylation. In fact, the reaction product is freed of excess alcohol and water formed by the reaction and finally distilled. The low yield is due to the fact that N-(.alpha.-alkoxyethyl)formamide is so poor in thermal stability that it decomposes during distillation.
In view of the foregoing, the present inventors extensively studied the production and thermal stability of N-(.alpha.-alkoxyethyl)formamide. As the result, we unexpectedly found that it is possible to produce thermally stable N-(.alpha.-alkoxyethyl)formamide in high yields by using a specific basic catalyst. This finding led to the present invention.